Abstract 15777: Association Between Sleep Disordered Breathing, Obstructive Sleep Apnea and Incident Cancer: A Systematic Review and Meta-Analysis
Introduction: Sleep disordered breathing (SDB) and obstructive sleep apnea (OSA) increase risk for multiple morbidities such as cardiovascular events, diabetes mellitus, and hypertension. Association between SDB and incident cancer is unclear and studies that assessed this association have yielded conflicting results. Hypothesis: We systematically reviewed the literature and pooled available evidence that has associated SDP and incident cancer. Methods: Medline, Embase, Cochrane central library, and electronic databases were searched for relevant studies. Studies were included if: 1) they studied patients with SDB, and 2) reported rates of incident cancer. We excluded studies that reported cancers involving head and neck as we suspected reverse causation, since head and neck cancers can lead to SDP. Data were pooled using a random-effects model. Results: From 3522 retrieved citations, 7 observational studies were included in the review. Of these, 4 studies, representing 48,152 patients with SDB and 87,849 patients without SDB, were included in the meta-analysis. In total 6931 incident cancer cases were reported (2813 in SDB group and 4118 in non-SDB group). In the pooled analysis, patients with SDB experienced higher odds of incident cancer (OR: 1.30, 95% CI: 1.06 - 1.60, P = 0.01, I 2 : 75%, 4 included studies) compared to those without SDB. Data from 2 studies that assessed patients with OSA, showed that OSA increased risk for incident cancer at 5 years follow-up (OR: 1.90, 95% CI: 1.46 - 2.45, P < 0.001, I 2 : 0%) and 8 years follow-up (OR: 1.54, 95% CI: 1.25 - 1.88, P < 0.001, I 2 : 0%). Also, cancer risk (OR: 1.28, 95% CI: 1.09 - 1.51, P = 0.003, I 2 : 21%, 2 studies) and cancer mortality (OR: 1.84, 95% CI: 1.32 - 2.56, P = 0.003, I 2 : 0%, 2 studies) was significant only in patients with severe OSA [apnea-hypopnea index (AHI) > 30] and not in patients with mild to moderate OSA (AHI < 30). Factors namely; obesity, type of cancer, age and gender did not account for between study heterogeneity. Conclusions: SDB and OSA are associated with incident cancer. Though our study did not support the role of obesity in this association, strong mechanistic link exists, associating SDB, obesity and cancer. Future studies should assess the association between SDB and organ specific cancers.